


The Upbringing of Superheroes

by SupercatFanatic



Series: Finding your way (in the deep Ocean) [1]
Category: Supergirl (TV 2015)
Genre: Alternate Universe, F/F, Kara as Mera, Lena as Aquaman, SuperCorp, aquaman au
Language: English
Status: Completed
Published: 2019-03-31
Updated: 2019-03-31
Packaged: 2019-12-29 18:11:45
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 5,074
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18299465
Author URL: https://archiveofourown.org/users/SupercatFanatic/pseuds/SupercatFanatic
Summary: This is the story of how Lena got in touch with her Atlantean heritage and how Kara became a strong fighter for Atlantis, how two lost little girls became strong women ready to save the world.ORThe prologue to the Aquaman AU that no one asked for.





	The Upbringing of Superheroes

**Author's Note:**

> Hello everyone! 
> 
> First of all, I'd like to remind you that I'm not an English native speaker, I'm French, so there might be some mistakes since I don't have a beta-reader. Feel free the tell me about them in the comment section or on Tumblr (@Xazera)!  
> Now, this is a prologue of some sort, the real story starts next week with the second part of the collection and I tried to make sure you could understand it without seeing the movie but I wanted to have some upbringing for our ladies and decided to write a chapter out of it.

_On the Surface..._

Lena was sitting at the front of the Luthor’s yacht, crosslegged, facing the ocean. She enjoyed the wind on her face, her hair tickled her face and even though she was hiding under a large hat her mother insisted she wore, she could feel the heat of the sun on her skin. She had always felt much more comfortable in cold weather but the change was nice. The smell of the ocean, the saltiness in the air and the freedom that seemed to emanate from it made her love the weekends on the Luthor’s yacht. Even with all the other people around, she felt more at ease than ever, which was weird, considering that she had this odd fear of water and didn’t know how to swim yet, even though she was six and Lex had learnt when he was five. His father had told her once, when she was only four, that learning about the ocean and what lives in it would make the fear go away eventually because nothing was scarier than the unknown. She had started to read books about fishes, seaweed and current. Soon enough, the tides held no more secret and she had developed a passion for the depths. She was still feeding her thirst for knowledge at the moment, a large book on cetaceans on her lap, her eyes running across the words eagerly. 

"Still reading, nerd?"

A boy, barely older than Lena, was standing behind her and she could already feel the annoyance rising. She hated her parents’ friends and she hated their children even more. They were entitled, spoiled and disrespectful. It usually was Lex who shielded her from them, diverting their attention so she could enjoy her peaceful reading. This one must have slipped away and decided to bug the silent kid. She wouldn’t make his game, Lex had told her to just dismiss them, she would do exactly that.

"Yes."

Her tone was so cold and distant, Lillian would be proud of her, but the kid wouldn’t let her off so easily, he kept going. 

"What’s the point? It’s not like you’re ever going to see it. You don’t even know how to swim."

Lena rolled her eyes at that, a bad habit according to her mother. 

"I learn about space too and I have no intention of going up there. I just don’t want to be ignorant like you."

She almost felt proud of herself for her comeback, she wasn’t usually good at that. But she also knew that she had angered him and this could mean trouble. 

"What did you just say to me?"

She closed her book and stood, her back to the sea as she tried to walk past him.

"Just leave me alone."

Lena had just reached his level when the boy pushed her away by the shoulder. Startled, she let her book fall from her arms, it hit the deck and bounced back, slipping through the bars and into the water. She tried to catch it by running after it but her legs were still sleepy from all the hours reading and she stumbled. She felt her whole body falling, she hit the guardrail and saw the water getting closer and closer. She let out a scream and closed her eyes. Soon enough she was deep inside water, the cold surrounding her as well as a great silence. She wanted to panic, to scream. Everything was dark and she didn’t know how to come up. Moving only made her go further down and she knew she had to calm down. She opened her eyes, slowly, expecting the water to hurt her eyes like her brother told her it did, but instead she discovered a whole new world. She could see fishes, coral and luminescent seaweed. She could see shellfishes on rocks and feel the current on her skin, the temperature was ideal and she felt oddly comfortable. She slowly turned around, trying to take in the beautiful scenery in front of her. She recognized several fishes from her books, there were Clown fishes, Moorish idols, Sweetlips, Emperor Angelfishes, Butterfly fishes, colorful anemones… It was amazing, everything she saw in her books and at the Aquarium was in front of her and she wanted nothing more than play with them even though she wasn’t quite sure how to move around. She held out her hand towards them, hoping they would come to her. She knew they heard her request immediately because they told her so. In a matter of second she was surrounded by dozens of fishes. They tickled her face, hid in her hair making her giggle. She held out her hand and surely two Butterfly fishes started suckling softly on her palm, they were absolutely beautiful, their bright yellow scales with soft stripes on it, shining. She wanted to stay here forever, play with her new friends that weren’t judging her or mocking her for reading too much or for being adopted. She understood now what her father told her, the fear was in the unknown. She knew now and she wasn’t afraid anymore. Lena didn’t know for how long she stayed underwater but she still wasn’t lacking air so it probably wasn’t that long. 

She heard before she saw someone plunge in the water next to her, making all of her new friends go away. The person grabbed her and together they went back to the surface. The sunlight was getting brighter and the world louder. She recognized her father and put her small arms around his neck. He brought her back to the boat and she was soon covered by a soft towel, her father looking at her worryingly. He noticed the copper shade in her eyes, mixing with the bright green that she inherited from him, and he knew that everything would be different from now on.

"Are you okay, Lena?"

Lena couldn’t shake off the smile from her face. She nodded joyfully at her father, holding the towel a bit tighter around her. 

"Yes, but I think I’d like to learn how to swim now."

**********

_Somewhere in an Atlantean School..._

Kara loved learning. She was excited to know about the world, about other people. Her brain was always hungry for more, especially when they learnt about the Land People. It seemed like an amazing place, with very different people and culture. She dreamed of visiting one day. Unfortunately, she was almost the only one who seemed to look forward to see the world. The other kids were often bored when it was time for history lessons and the teacher appeared to have a sort of hatred for the surface that Kara couldn’t comprehend. She was only eight years old but she was very clever for her age and it pained her to see that adults could be so narrow-minded. 

She raised her little hand, ready to fire her questions like she often did. She saw the teacher sigh but ignored him, her parents had told her to never cease to be curious and to seek for knowledge, always. The teacher put a smile on his face and nodded at Kara. 

"Sir, why do our people hate the surface?"

"It’s not that we hate them. It’s their disrespect that we don’t like."

He could see the frown on her face and chuckled. 

"We live in the ocean and we make sure to take care of the planet we live in. We learnt to live with sea creatures and how to make sure we do nothing to harm the planet. But the Land People, they don’t have the same consideration and they make it hard for us to live in the ocean. They pollute it and they kill everything they see."

"Maybe they don’t know any better, they don’t have our technology, maybe they would do better if they had it?"

The teacher shook his head, the other kids were getting agitated and he didn’t have time to answer all of the little girl’s question right now.

"I don’t know, Kara. Each time they get new technology they use it to kill each other or the planet."

"But we could help them, teach them about what we know and…"

All the kids were laughing and talking over her, she could barely get her thoughts in order and the teacher didn’t seem to really be understanding her point. Since she arrived at the Danvers, she had always had trouble with noise. Eliza called it a sensory overload, when all the noises became stronger and drowned her mind. The world then became blurry and her head started spinning. She was almost certain that she was having a sensory overload.  
She was getting frustrated and the room was getting louder and louder. So much that her head started pounding. She put her her hands over her ears and closed her eyes, for the first time in her life she felt like she couldn’t breathe, as if she was drowning which made no sense, she wished for something new, for freshness, silence. It was the worst it had ever felt since her parents’ death. The cloud around her mind was getting darker and trying to get it away she let out a scream that probably shocked everyone around her but she was too deep in her own head to care. She immediately felt something different, colder, lighter. A weight had been lifted from her shoulders but she still couldn’t get herself to open her eyes. She hid her head in her arms and tried to breathe. 

 

The teacher had pushed all of the children out of the way as soon as he had understood what was happening. He had witnessed things like this before, but rarely in such a young child. He was looking at the small blonde, lost on her desk, there was a sort of bubble around her and her desk and he had seen it before when he came across air pockets in the old city. The girl was probably having a panic attack and he couldn’t reach out to her. Only high-borns could breathe out of water and he wasn’t one of them, none of the children in her classroom were. 

"Everyone out of the classroom, now."

He led the children out of the room, afraid that the air pocket would grow more and swallow them up. When he got to the hallway they saw that the rest of the school had gathered in front of the classroom and he told them to all leave the building. One of the other teacher came up to him to ask what it was about. 

"It’s Kara Danvers, we need to get to her parents."

A little girl with long dark hair and a frown on her face made her way through the crowd. She passed the teachers and swam quickly to the classroom. 

"Alex, come back! It’s not safe!"

But the girl didn’t listen to them. She entered the classroom and jumped in the air pocket without a second thought, her little sister was in here and needed her. As soon as she felt the air on her face it felt like she couldn’t breathe. Something burnt inside her chest and she crouched over as water left her body. It hurt her throat and she could feel the cramp in her abdomen as she threw up. It lasted a few seconds and she put everything she was feeling aside to get to her little sister. She saw her with her head against the table, panting hard. Alex walked slowly towards the blonde, she looked even smaller than usual. She kneeled next to her to try and catch her eyes but they were closed. 

"Kara, can you hear me?"

Her voice was rough and it really hurt to talk. Alex had never gotten sick in her life, ever. And throwing up was painful as hell. Ignoring it, she saw her sister nod. 

"Okay, don’t open your eyes yet, I need you to tell me what’s wrong."

Kara’s voice was wet, she had been crying.

"It was so loud, Alex…"

Alex noticed the teachers gathering outside the bubble, she couldn’t hear them talk and she somehow knew they couldn’t hear them either which explained the deafening silence around the two of them. 

"It’s alright, listen, there’s no more noise."

"Is everyone gone?"

 _Not exactly…_ thought Alex, but it really wasn’t the time to tell Kara that she had just conjured a bubble that could have killed everyone in her class.

"Yeah, Kar’, it’s just us. I’m gonna hug you now, is that cool with you?"

When Kara acquiesced she turned her chair to take the blonde into her arms. Alex was barely ten years old, but when Kara first arrived at the Danvers, she knew she would always have and want to protect her with her own life, even if she tried to hide it. Her sister was the most joyful person ever, despite losing her family very young and having to go and live in a new culture. Right now, she knew Kara would panic if she saw the situation they were in and they didn’t need that, at all. She hoped she did the right thing when she made Kara stand up and follow her while still in her arms.

"You trust me?"

Kara nodded against her shoulder.

"You keep your eyes closed and you walk with me."

"But…"

"Please, Kara?"

"Okay."

Alex prayed for her parents to arrive already, because she really didn’t know what was going to happen when they left the air pocket, hopefully it wouldn’t blow up… They backed up and Alex felt water on her back, the comfort of being in her element bringing back her confidence. She walked fully into the water, Kara with her, and as soon as they were fully emerged, the whole air pocket disappeared, filled again with water. Kara opened her eyes wide when she noticed the different feeling. 

"Alex, what happened?" 

She was about to answer when her mother entered the room with a scared look on her face. She immediately floated to them and took them both in her arms. 

"Are you both okay?"

They both nodded, Kara had tears in her eyes now, she didn’t understand what was happening, at all. 

"You’re fine, sweetheart. We’re going home, we’ll talk there."

*

They entered the huge palace in which the Governor’s family lived, immediately going to the kitchen because Eliza knew both her girls would be hungry after so many emotions. They all sat at the kitchen table and while Kara all but devoured her snack, Alex started questioning her mother. 

"So mom, want to tell us what the hell happened back there?"

Eliza rolled her eyes.

"Language, Alex."

"Sorry, but really, what was that?"

Kara was frowning, looking at her hands. 

"It wasn’t just a panic attack?"

Alex shook her head and looked at her mother with a questioning look and told Kara what she saw when her mother nodded at her.

"It was like… a huge air pocket but just around you?"

"But that’s not possible, is it?"

"Actually I’m not really surprised."

Both girls turned towards their mother and waited for her to continue. 

"Kara, you’re a descendant of Krypton and your parents were both high-borns. It was a possibility that you would develop some sort of ability. It’s not unseen, I just didn’t know what it would be."

"Is it… Can it be dangerous?"

Kara was getting worried but she felt Alex’s hand in hers and relaxed a bit.

"Only if you’re scared of it. We will teach you how to control it, okay? But Alex, what you did was reckless, you didn’t… How did you know you would be able to breathe?"

Alex shrugged. 

"I didn’t, I just wanted to get to Kara, it was the first time she had a panic attack at school."

Kara hit her sister on the arm.

"You idiot! You could have been hurt!"

The brunette rolled her eyes and pushed Kara’s hand away. 

"Look, I’m fine, okay? Spitted some water and got you out of it. Don’t make a big deal out of it…"

Kara and Eliza both knew it was a lost cause so they let it go. The older woman was just glad both of her daughters were safe. 

**********

_A few years later, on the Surface..._

It was a rainy summer day, the ocean was agitated, large waves crashing on the Luthor’s private beach. Lena was sitting by the water, contemplating if she wanted to get back in for another hour or if she should go back now. She had been swimming for hours but her heart wanted more, it ached for the stillness and colors of the ocean. Since her trip in the water four years ago, she had leant how to swim and quickly became the strongest swimmer in the whole class. Her arms never tired, she was never out of breath and she always knew where she was going. The swimming pool soon became constricting, she was trapped inside so she started spending her free time swimming at the beach. Lillian tried to fight it at first, telling her she needed to learn how to play music, to dance or to focus on her studies, but with Lionel help, she soon understood that she couldn’t keep her daughter from the water. 

The rain was falling down her face as she stood and walked towards the water. One last hour and then she would go home. 

She was about to plunge when something… no, someone, came out of the water and walked up to her. He was a tall, black man with a serious face. Lena was shocked, this was their private beach and she was alone on it, the weather didn’t really called for a trip to the beach anyway. Once the man reached her, he smiled. 

"Lena Luthor, I am J’onn J’onnz, we need to talk."

Lena grabbed her soaked towel and put it around her, frowning.

"How do you know my name?"

"I think we should find somewhere to talk."

Lena snorted, she was ten but not stupid. 

"I can’t really well follow a stranger, can I?"

The man nodded and gestured to the ocean. 

"How about somewhere you’re familiar with?"

Lena hesitated but acquiesced, walking behind him and into the water. She didn’t really know how they would be able to talk in the water but at least she would get to be somewhere safe. They plunged together and she swam a bit ahead of him, getting into her favorite spot, a little crook in a deeper part of the shore. J’onn followed her, sitting quietly beside her. Lena looked at him curiously and waited, as if something could happen. 

"I am here to tell you about your origins, about who you are."

"You can talk underwater?"

Lena put her hand in front of her mouth in shock, she had just talked under water! 

"I… Why? It shouldn’t be possible. I read that…"

"Humans can’t breathe underwater, but you’re not really human so that doesn’t apply to you."

"I am not… Okay, this doesn’t make any sense."

J’onn swam in front of her, looking at her eyes and smiling. 

"I am going to tell you a story, your story, the story of your birth, it will be up to you to believe me but your father will be able to confirm everything."

At the mention of her father Lena perked up and nodded. 

"Eleven years ago, the Queen of Atlantis, Atlanna, fled her Kingdom to escape an arranged union. In doing so, she washed up in Ireland where your father was staying for the time being. During their brief time together they fell in love. Nine months later you were born but your father couldn’t stay with you and your mother. He was married and had a life in the United States. Your mother didn’t want to go back to the ocean and leave you behind so she raised you, for the first four years of your life. She loved you with all her heart but Atlantis… Atlantis is many things, but forgiving is not one of them. The King sent soldiers after her and eventually they found her. She fought them, pushed them away, but she knew they wouldn’t leave her at peace as long as she stayed on land, with you. So she called your father, he would take care of you and she would return to Atlantis so you could grow up free."

Lena was listening with rapt attention. She had never heard about her birth mother, her father refused to talk about her and her mother always got angry each time she was mentioned. The last memory Lena had of her mother was a sad one, one that scared and saddened her at the same time. She could remember her dark hair, her naked feet and the bright red dress she had been wearing when she walked into the ocean, leaving Lena on the shore to watch her disappear. She had told her she loved her then, promised her they would be reunited one day. She remembered crying a lot, until her father picked her up and took her to the United States. She hadn’t wanted to go near the water after that. But she was ten now, she had learnt that the ocean was not her enemy. She also was clever for her age and she knew there was no such thing as Atlantis, right? It was just a legend, a myth told to children to entertain them. 

She realized she hadn’t said a word in too long and J’onn was looking at her worriedly. 

"I… It’s a lot to take in. Atlantis, it can’t be real."

J’onn chuckled. 

"Then explain to me why you’re able to talk underwater, or the fact that you don’t need to come up for air like humans do?"

"I can’t. But you… You could show me evidence that it exists, you can take me there! If it’s real then I could see my mother again…"

Lena was looking at J’onn shyly, ready to leave. 

"Show me it’s real, please, let me see her again."

J’onn smiled sadly at her and put his hand on her shoulder. 

"When you’re ready, I’ll take you there. But for now, you have to go home, talk to your father. I’ll come back, I’ll teach you about Atlantis, I’ll train you to master your abilities."

Lena agreed and went to her father’s office immediately. He told her everything and confirmed what J’onn had told her. He also asked her to never talk about this to anyone, not even her brother or mother. 

"You have to understand, Lena, that humans don’t like what is different. I want you to be safe, more than anything, so if you want to explore this, fine, but you have to do it in total secret."

Lena had understood so she promised her father and waited excitedly for the day she would get to see her mother again. 

***********

_A regular Sunday morning in Atlantis..._

"Come on, Kara, get your ass up! It’s training day!"

Alex heard her sister groan from somewhere in her bed and took the covers away from her. 

"I didn’t quite catch that, what did you say?"

"I said to watch your language, mom will hear you. And also, it’s Sunday, why can’t I sleep in?"

Alex rolled her eyes and threw Kara’s combat suit on the bed. 

"I’m eighteen, I’m pretty sure I can say whatever I want. And it’s not my fault if we’re the Governor’s daughters. Dad says it’s important we know how to defend ourselves. Also, your lazy a-butt still needs to master her special abilities."

This made Kara sit up in her bed. She was glaring at her sister. 

"I’m perfectly fine with my powers."

"Really? Well then, get up and show me."

The blonde rolled her eyes at the smirk on Alex’s face but did as she was told, she was going to kick her sister's ass…

…Or maybe not. Kara was lying on the floor, Alex had kicked her down once again and she was getting tired and frustrated. How could her sister be so much better than her when they started their training together? Well, she knew why. Jeremiah kept chastising her for it, it was because she relied on her powers to get out of trouble, and even though it was legit, they wanted her to be able to fight without it. But she had her sister’s stubbornness and so she never took combat classes as seriously as Alex did, meaning that now, she got her ass kicked.  
She was exhausted, every part of her body hurt and she could see that Alex was really enjoying beating her up. She groaned as she stood again, floating at Alex’s level. 

"Still not beating me, I see."

She saw that her sister was tired and took pity on her. 

"Want to take a break, we’ve been at it for three hours after all."

Kara shook her head, a determined look on her face. 

"Last one?"

Alex nodded with a smile and assumed her position. As soon as she gave the signal Kara swam towards her at an alarming speed and threw her fist at her sister. She dodged it easily, Kara was tired, her movements were slower, sloppier. Alex grabbed her arm, twisting it, and threw her into the ground. Kara would have crashed if it wasn’t for her quick reflex. She pushed herself off the ground, surprising even Alex, and grabbing her by her midsection. She trapped her between her body and the wall, ready to make the brunette surrender when she saw her smirk. She felt herself get thrown back into the opposite part of the room and just as Alex was about to finish her Kara closed her fists and bumped them together. Water started to flow violently on either part of Alex, not enough to knock her out but enough to stop her movements. She was protesting when the blonde smirked, opening her arms wide. The water in the room disappeared and Alex fell loudly on the ground with a groan. She immediately starting throwing up all the water in her body, leaving her weak and helpless. Alex was a great fighter, but not so much out of the water.  
Kara gently accompanied her fall with a wave, landing softly and gracefully next to her panting sister. 

"That was not fair."

Kara shrugged, a smirk still on her face.

"It is because this is my real combat skill."

"Whatever, you’re not supposed to use it when we’re training," before Kara could roll her eyes Alex continued, "but that was very well done. You really got a hang of these powers, uh?". 

Kara smiled and nodded. 

"J’onn’s training sessions are really demanding but they paid off."

She helped Alex stand again and stretched. 

"Yeah, he beats my ass every day, still can’t take him down."

"Me neither, he’s as good in water as he is out of it."

They both smiled, feeling exhausted and content. 

"Alright, I’m gonna close it. You ready?"

"Sure."

Kara closed her eyes, enjoying the last second of silence before they got swallowed by the water coming at them.

*********

_In Lena's penthouse, many years later..._

"Are you sure I don’t look ridiculous?"

Lena saw Jack rolling his eyes in the mirror. 

"No, you look gorgeous, very badass." 

It was the brunette’s turn to roll her eyes. She looked at herself in the mirror once more. The sea green material clung to her body like a second skin and the blue reflections on it were absolutely gorgeous. She would have to thank J’onn for providing Atlantis’ material that would resist the temperature variations, the abrasion caused by salt and would still allow her to move freely, wether it’s underwater or on the surface. It was covering her body from shoulders to feet, the vibrant color bringing out the green and copper of her eyes. 

"There’s just one thing missing!"

Lena sighed and turned towards her best friend. She was very grateful for him, he was the only one outside her family who knew about her lineage and even if he could be something of an asshole, he had always been supportive and kind to her, even after they broke up.

"This is ridiculous, I don’t see why I should wear a mask…"

He handed her the small mask they had designed a few days ago. 

"Because you’re freaking Lena Luthor and your face is everywhere. You can’t just go around super-heroing in your day to day outfits. You know it would be dangerous."

She brushed him off with a wave of her hand. 

"I know, I just… I feel ridiculous. I’m not sure if I’m doing the right thing."

He smiled softly and opened his arms. 

"Come here…"

She dropped on the couch and fell in his arms. He hugged her tight, kissing the top of her head. 

"We talked about that, Lee. You don’t have to do anything, you’re already helping the world so much with your work at L-Corp, but I’ve seen you helping others using your abilities, it makes you happy."

"My mother gave me up so I could have a normal life, but it just feels like a waste to ignore this part of me."

"Your mother isn’t here anymore, and you have a chance to help people, to actually save lives. And one day you’ll probably have to go to the Atlantis too, to show them how great you are."

Lena shook her head, getting out of Jack’s arms. She put on her mask, the light and rigid material covering the upper half of her face in the same color as her suit. She was a vision in her full attire, and even if she still had doubt about what she was doing, there was one thing she was certain about, Atlantis was nothing more to her than the distant family you never knew. They killed her mother and kept her out of her legacy. She took her mother’s trident and spun it, testing her movement when she was in the suit. After one last spin, she hit the floor with it and smirked at Jack.

"I don’t owe them anything. If Atlantis wants me, they will have to come and get me."

**Author's Note:**

> Sorry about the awfully long beginning notes! Was that okay? I need to know if you want me to change some things in my writing before I post the other chapters! 
> 
> The fiction will be seven chapters long and I will post every five days so make sure to subscribe to the collection and then to the fic if you want to be kept updated! 
> 
> Thank you so much for reading, you can come and talk to me on Tumblr (Xazera or SuperCat Fanatic),  
> Have an amazing Sunday, Xoxo, SCF :3


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